82 
A PRELIMINARY NOTE ON A TREMATODE 
PARASITE IN CARDIUM EDULE. 
By M. V. LEBOUK, B.Sc. 
Early in October, 1904, I examined about 20 cockles {Card him 
edule) from Budle Bay, Northumberland, and among them found 
one which had its foot covered with small tubercles, and another 
similarly but more slightly affected. On microscopic examination 
the tubercles proved to be encysted Trematode worms. 
Afterwards, in November, on examining a large quantity of 
cockles from the same locality I found about 10 per cent, had the 
the worms in the foot, but many more (about 75 per cent.) on 
microscopic examination were found to have a Trematode in the 
sporocyst stage round about the intestine and in the liver. All 
those that had the foot affected also had the sporocyst form, but 
many had the sporocysts without the worms in the foot. Mr. Shipley 
to whom I submitted the worms from the foot regards them as 
belonging to the genus Distoma and the sub-genus Echinostoma. 
As the sporocysts are evidently also a species of Distoma, they are 
probably the sporocyst stage of the encysted worms in the foot. 
The cockles are fine specimens, often 45 to 50 mm. in length, 
and, it may be added, vary much in form. 
The worms are enclosed in cysts inside the tissue of the foot, and 
can be teased out complete still enveloped in the cysts. On gently 
pressing one of these the worm may be squeezed out. The only 
successful method of mounting them appears to be in dilute 
glycerine ; glycerine jelly and Canada balsam both spoiling the 
appearance of the creature and often breaking it up. 
Thus disclosed (see Plate, fig. C) the worm is elongated, transparent, 
and granular. One end is broadly heart shaped and surrounded by 
long straight spines. At the very anterior end is a sucker and 
further back but still in the region of the spines is an opening 
